In water circulatory system, after the process of producing and consuming water, wastewater collection is intended.  Domestic or industrial wastewater is one of the pollution sources in environment, which is  normally released in nature and can pollute the environment; that is, water, soil and air. a lack of water resources doubly necessitates the recirculation of water by collecting and treating wastewater and reuse of it.

There are some different approaches to collect wastewater which are proposed by consulting engineers according to topography conditions, type of wastewater, the way of collection, accessible facilities and equipment. Gravity wastewater network is one of the most common  ways for wastewater collection throughout the world. In some specific cases, to add head to wastewater and prevent from deepening the network, pumping or lift stations are used. Similar to water networks, there are various software programs in design of wastewater networks, which Sewer-Gems is one of them.